1. Field of the Invention
The invention relates to a novel end-pressure connection device for electrically connecting at least two contacts in pin form and more particularly to constitute a connecting terminal or a power plug.
2. Description of the Prior Art
To constitute end-pressure connection devices with at least two contacts, it has been conceived to mount one of the contracts in a base provided with an elastic means designed to urge said contact directly so that the contacts are applied against one another with pressure.
However such devices necessitate the connection of the elastic contact with a flexible wire to give it the necessary amplitude of compression. It is clear that such devices are unusable for numerous applications. This is why it has been conceived to constitute connectors and power plugs with end-pressure contacts by means of a hollow or solid conductive tress. Such connectors include, on the one hand, a "fixed" elastic contact formed from a wire grip or fixed lug, a tress, a spring and a contact head urged by said spring and, on the other hand, a movable pin contact formed from a wire grip or lug and a pin.
End-pressure contacts including a tress have numerous advantages in their applications. However difficulties appear at the level of connecting the parts constituting the fixed elastic contact as well as in the manufacture of the tress. In fact, it is necessary to obtain, for such devices, good elasticity of the tress with maximum passage cross-section for the current, high reliability of the tress on manipulation and lastly wire grip-tress and tress-contact head connections which result in a minimum voltage drop over time.
To obtain good elasticity and correct reliability of the tress, the wires of the latter must be selected to be very fine while their tress formation must be particularly careful. In addition, the cross-section of the tress is tied up with the dimensions of the equipment to be produced, which makes it possible only with considerable difficulty to achieve a tress cross-section equal to that of the conductors, especially for large cross-sections.
As regards the connections, it is possible to select between brazing and crimping. However brazing has the drawback of annealing the strands of the tress, which reduces its reliability on manipulation, whilst crimping which has greater reliability never gives a certainty of minimum voltage drop in time, which causes a risk of heating. Moreover, the force of plugging in such a device must not only overcome the compression of the spring, but also that of the tress.
It is therefore an object of the invention to provide an end-pressure connecting device wherein the voltage drop of the device is guaranteed over time since contrary to tressed devices, the voltage drops only exist at the points of contact.
It is another object to provide an end-pressure connection device which eliminates the drawbacks of brazing or of crimping of a tress and hence results in greater reliability of the device.
Another object of the invention is to provide a device in which the cross-section of the bar can be equal to those of the conductors, which reduces electrical resistance and hence heating.
Yet another object of the device according to the invention is simplification with respect to known tressed devices and elimination of checking the crimping and the like, which results in a reduction in cost price.
A further object is to provide a device in which the contacts are self-cleaning, on account of the friction of the pins on the studs at the moment of the placing in contact, due to the elastic movement of the bar.